From: Andrew Morton <akpm@linux-foundation.org>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Michal Hocko <mhocko@kernel.org>, Hugh Dickins <hughd@google.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Davidlohr Bueso <dave@stgolabs.net>,
Prakash Sangappa <prakash.sangappa@oracle.com>
Subject: Re: [PATCH v2 0/2] hugetlbfs: use i_mmap_rwsem for better synchronization
Date: Thu, 20 Dec 2018 13:06:42 -0800 [thread overview]
Message-ID: <20181220130642.e43bee30cf572c5a9a3a8557@linux-foundation.org> (raw)
In-Reply-To: <20181218223557.5202-1-mike.kravetz@oracle.com>
On Tue, 18 Dec 2018 14:35:55 -0800 Mike Kravetz <mike.kravetz@oracle.com> wrote:
> There are two primary issues addressed here:
> 1) For shared pmds, huge PTE pointers returned by huge_pte_alloc can become
> invalid via a call to huge_pmd_unshare by another thread.
> 2) hugetlbfs page faults can race with truncation causing invalid global
> reserve counts and state.
> Both issues are addressed by expanding the use of i_mmap_rwsem.
>
> These issues have existed for a long time. They can be recreated with a
> test program that causes page fault/truncation races. For simple mappings,
> this results in a negative HugePages_Rsvd count. If racing with mappings
> that contain shared pmds, we can hit "BUG at fs/hugetlbfs/inode.c:444!" or
> Oops! as the result of an invalid memory reference.
Still no reviewers or ackers :(
I'll queue these for 4.21-rc1. The Fixes: commits are over a decade
old so I assume things aren't super-urgent and the cc:stable will do
its work.
prev parent reply other threads:[~2018-12-20 21:06 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-18 22:35 Mike Kravetz
2018-12-18 22:35 ` [PATCH v2 1/2] hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization Mike Kravetz
2018-12-19 1:24 ` Sasha Levin
2018-12-21 10:05 ` Kirill A. Shutemov
2018-12-21 18:20 ` Mike Kravetz
2018-12-18 22:35 ` [PATCH v2 2/2] hugetlbfs: Use i_mmap_rwsem to fix page fault/truncate race Mike Kravetz
2018-12-19 1:24 ` Sasha Levin
2018-12-21 10:28 ` Kirill A. Shutemov
2018-12-21 18:28 ` Mike Kravetz
2018-12-21 20:21 ` Kirill A. Shutemov
2018-12-21 22:17 ` Mike Kravetz
2018-12-22 22:14 ` Kirill A. Shutemov
2018-12-20 21:06 ` Andrew Morton [this message]
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